NX is an exciting new technology for remote display. It provides near local speed application responsiveness over high latency, low bandwidth links. The core libraries for NX are provided by NoMachine under the GPL. FreeNX is a GPL implementation of the NX Server and NX Client Components.

Installation

Get the server nx-all from the AUR. Both server and client packages are included in the package.
The sshd daemon (available in openssh package) must be installed and running for it to function properly.

Setup

Server

SSHD

For freenx authentication to work, sshd has to be setup properly.
You need to allow RSAauthentication, Password Authentication, and you also need to include nx public keys to Authorizedkeysfile.

If you do not want to allow password login globally, add match block at the end of file like below: /etc/ssh/sshd_config:

MAIN CONFIGURATION

The main configuration file is located at /usr/NX/node.cfg.

If you are running your SSH daemon on a port other than the default port 22, you'll need to uncomment and update:SSHD_PORT=22

If you use KDE or Gnome desktop environments you do not need to edit this file, as the defaults with the modified MD5SUM command should work in this case. If you use another window manager such as Fluxbox/Openbox or Xfce, you may need to edit this file slightly (see below).

Or if you are not using CDE but Xfce you could simply edit CDE line like below:

CommandStartCDE = "/usr/bin/startxfce4"

After installing the nx-all package, run sudo /usr/NX/scripts/setup/nxserver --help for an overview of the install and uninstall procedures.

Note:

You should also install xdialog on the server or you will not see the "suspend/terminate" dialog when you try to close the window or hit Ctrl+Alt+t.

Although mostly assumed that you will have it already, xterm is also necessary for some things.

Keys

Keys are used to authenticate the clients with the server. By default a new set of random keys are generated during the install, one for the server and one for the clients. You will need to copy this client key to each of your clients that want to connect (Windows and Linux).

The client key can be found here:

/var/lib/nxserver/home/nx/.ssh/client.id_dsa.key

Alternatively you can use the default key that is provided by NoMachine with all clients. In this case you do not need to copy a custom generated key to each client. To get the server to accept the default client keys run:

Starting the server

Once installed the server is effectively running and ready to go, you do not have to do anything manually. The only thing that must be running in order to connect is the sshd daemon. This is because the nxserver is actually started by logging into sshd as the special user 'nx'. This user has been set up to use the nxserver as its shell, much like a normal user has bash as the default shell.

You can specify the local addresses sshd should listen for by editing /etc/ssh/sshd_config and adding them in the following format:

ListenAddress host|IPv4_addr|IPv6_addr

The original ListenAddress in sshd_config is 0.0.0.0. This listens to all addresses, however adding any address will take precedent to this and and accept connections from the new address only.

Restart the sshd daemon to put any changes to its configuration into effect.

In actual fact, if you check the process list (ps aux) you may not see the nxserver running even though it is. This is because the nxserver is actually started by logging into sshd as the special user 'nx'. This user has been set up to use the nxserver as its shell, much like a normal user has bash as the default shell.

Client

Arch Linux

Windows

Tip: Nomachine tends to remove old clients from their homepage,
If your setup works with a client save it in a safe place.

Configuration

As mentioned above, the client must contain the correct key to connect to the server. If you are using the custom keys generated during install, you need to copy the client key to the following locations:

Windows: your_install_dir_on_windows/share/keys/client.id_dsa.key

Arch Linux: /usr/lib/nx/share/keys/client.id_dsa.key

After moving the keys you may have use the nxclient GUI to import the new keys. From the configuration dialog press the 'Key...' button and import the new client key.

Running

After installing nxclient on Arch Linux, executables are available in /usr/lib/nx/bin/ symlinked to /usr/bin/. At the first run of /usr/bin/nxclient, the user will be led through a wizard.

Keyboard shortcuts

CTR+ALT+F Toggles full-screen mode.
CTRL+ALT+T Shows the terminate, suspend dialog.
CTRL+ALT+M Maximizes of minimizes the window
CTRL+ALT+Mouse Drags the viewport, so you can view different portions
of the desktop.
CTRL+ALT+Arrows
or Moves the viewport by an incremental amount of pixels.
CTRL+ALT+Keypad
CTRL+ALT+S It will activate "screen-scraping" mode, so all the GetImage
originated by the clients will be forwarded to the real
display. This should make happy those who love taking
screenshots ;-). By pressing the sequence again, nxagent
will revert to the usual "fast" mode.
CTRL+ALT+E lazy image encoding
CTRL+ALT+Shift+ESC Emergency-exit and kill-window

Leaving fullscreen

There is a magic-pixel in the top right corner of nearly every nx-application
in fullscreenmode. Left-click the pixel and application-window gets iconified.

Tips on resume

Resume is a bit experimental, crashes might appear after session has resumed. You have to find out which apps like resuming and which do not ;) .

Resuming between Linux and Windows sessions does not work. UPDATE: It appears that version 3.2.0-14 is able to resume Windows-suspended sessions.

If resume fails let it time out and do not use the cancel button, else sessions will stay open and consume RAM on server. To kill such sessions use the Session Admin program to kill them.

Fix DPI settings

If you like to have the same font-sizes/dpi sizes on all your client session,
set the X resource "Xft.dpi". For example putting the following line into a
user's "~/.Xresources" makes her/his "desktop" a 100dpi.
Xft.dpi: 100

FreeNX to existing display

Usually, when connecting to a NX server, a new X session is created. Sometimes it might be useful, to connect to an existing X session, e.g. the root session. This is not possible with NX in default setup, but can be reached, using tightvnc and x11vnc. Install them on the NX server system.

x11vnc will serve the X session, we have to create a file $HOME/.x11vncrc to give x11vnc some options, e.g.:

Create a shell script, which starts the x11vnc service, if not running and starts the vncviewer provided by the package tightvnc.

Note: The variable $VNC_PORT in the following script defines the X display, which is configured as display :0 under $HOME/.x11vncrc, 5900 is the root session, if you want to use display :1 use the port 5901 and so on

Setting up non-KDE or Gnome desktop managers

Before following anything in this part, make sure the server working setup and accepting connections. This section only deals with problems once NXClient has logged on.

It is quite simple (once the server is setup) to connect to Gnome and KDE sessions, however connecting to other window managers (Fluxbox, XFCE, whatever) is slightly different.

Choosing "custom" and using a command like startx of startfluxbox will either result in a blank screen after the !M logo or the Client to present an error complaining about lack of a X server. A way around this is open a session with the command "startx", and the another with the command to start your window-manager-of-choice.

(Authors note: This is how I got fluxbox, xfce and others to work on my arch installation- however, I have now removed slim from inittab and set the run level back to 3, and yet I can still login perfectly with NXClient. Possibly try this if you get your system working this way, if like me you have a low memory machine.)

Note: The above information may not be true anymore. Once connection and authentication were valid (and xterm was installed on mine), startfluxbox was added to the custom command line, new window was selected, and it started right up.

Alternative fix

A simple fix without resorting to the above seems to involve a simple edit to the config file. This should work for Fluxbox/Openbox/XFCE or any other window manager that uses the .xinitrc startup file in a call to startx.

Simply edit the config file /etc/nxserver/node.conf as root and change:

#USER_X_STARTUP_SCRIPT=.Xclients

to:

USER_X_STARTUP_SCRIPT=.xinitrc

Remember to remove the # symbol from the start of the line.

Then in the client under configuration settings, choose Custom as the desktop, and click on settings:

In the first group select - Run the default X client Script on server

In the second group select - New virtual desktop

Problems

Debug problems

Edit the nxserver config file /etc/nxserver/node.conf and change:

#SESSION_LOG_CLEAN=1

to

SESSION_LOG_CLEAN=0

Then you can look/debug the log files in:

$HOME/.nx/T-C-hostname-display-session-id

For succesfull connections and:

$HOME/.nx/F-C-hostname-display-session-id

For failed ones.

Authentication OK, but connection fails

If you are trying to start KDE edit /etc/nxserver/node.conf and search for:

COMMAND_START_KDE=startkde

Replace for:

COMMAND_START_KDE=/usr/bin/startkde

Key changes

Change the key in GUI setup to new generated key.

Xorg 7

Be aware that you have to remove the /usr/X11R6 directory, else strange things
can happen.

Wrong password / No connection possible / Key-based authentication

If you have changed your ssh daemon to run on an alternate port, be sure to modify SSHD_PORT within /etc/nxserver/node.conf.

If you get always wrong password or no connection after authentication was done and you are sure that you typed it correct, check that your server can connect to itself using localhost by ssh.

If you messed up your key files, create new ones or fix the old ones, it's probably caused by a wrong known_hosts file.

If you get wrong password or login, put ENABLE_PASSDB_AUTHENTICATION="1" in /etc/nxserver/node.conf and add a user by

Awesome WM

NX logo then blank screen

If you see the NX logo (!M) then a blank screen.

This problem can be solved by running a login manager- The problem is that X11 is not started, and it appears that "startx" or similar do not work from the freenx client.
Follow these instructions to setup a login manager and load it at startup: Display Manager

Blind: If this does not resolve your issues, be aware that freenx and bash_completion do not play well together. I only got things to work after removing bash_completion from the .bashrc.

Broken resume with Cairo 1.12.x

Latest cairo updates broke the render extension. After resuming a session all characters from before suspending won't get rendered. To fix this add this single line to /etc/nxserver/node.conf.

AGENT_EXTRA_OPTIONS_X="-norender"

Eclipse crashes when editing a file

The program 'Eclipse' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadValue (integer parameter out of range for operation)'.
(Details: serial 8414 error_code 2 request_code 149 minor_code 26)